1/5/09

Post date: Jan 04, 2009 9:37:37 PM

Bell Activity:

    • Just like elements, we give names to compounds to separate them from other compounds

    • Naming ionic compounds

      • Ionic compounds are formed because of attractions between positive and negative ions.

        • Positive ions

          • are positive because they gave up electrons (lost negative charges)

          • are called cations

          • Are usually formed by elements on the left side of the periodic table

        • Negative ions

          • are negative because the gained electrons (gained negative charges)

          • are called anions

          • Are usually formed by elements on the right side of the periodic table

      • Naming cations

        • use the name of the element, plus the word ion

        • ion charges are determined by number of valence electrons

        • cations will have + charge, with the charge number being the same as the number of valence electrons

          • Example: Sodium, Na

            • When sodium gives up electrons, it becomes an ion called sodium ion

            • Sodium is in the first column of the periodic table, so it has 1 valence electron

            • The charge of a Sodium Ion is 1+, so the symbol for this is Na 1+

          • Example: Barium, Ba

            • When barium gives up electrons, it becomes an ion called barium ion

            • Barium is in the second column of the periodic table, so it has 2 valence electrons

            • The charge of a Barium Ion is 2+, so the symbol for this is Ba 2+

      • Naming ions assignment

          • Write the name and symbol of the ions formed by the following elements:

            • Lithium

            • Beryllium

            • Calcium

            • Cesium

            • Potassium

          • Example: For Sodium, the name of the ion is Sodium Ion and the symbol is Na 1+

          • We will add to this assignment, so don't turn it in yet

        • Some elements (transition metals) form more than one type of cation

          • With these elements, we must include some way to show which ion we're talking about

          • We do this with roman numerals to show the charge of the ion

            • Example: Iron, Fe

              • Iron can give up either 2 or 3 electrons, so it will have either a 2+ or 3+ charge

              • The Iron ion with a 2+ charge is written as Iron (II) ion

              • The Iron ion with a 3+ charge is written as Iron (III) ion

      • Naming Anions

        • use the name of the element, but change the ending to -ide, plus the word ion

        • ion charges are determined by valence electron numbers

        • cations will have - charges, with the number determined by how many electrons they can take

          • Example: Chlorine, Cl

            • When chlorine receives an electron, it becomes Chloride ion

            • Chlorine is in the 7th column (has 7 valence electrons). This means the chlorine takes one more electron, or one negative charge.

            • The charge for this ion, then, is 1-

            • The symbol for the Chloride Ion is Cl 1-

          • Example: Nitrogen, N

            • When Nitrogen receives an electron, it becomes Nitride ion

            • Nitrogen is in the 5th column (has 5 valence electrons). This means the Nitrogen takes 3 more electron, or 3 negative charges.

            • The charge for this ion, then, is 3-

            • The symbol for the nitride ion is N 3-

      • Naming ions assignment

          • Write the name and symbol of the ions formed by the following elements:

            • Bromine

            • Sulfur

            • Phosphorus

            • Astatine

            • Oxygen

          • Add this to the cation naming practice we did earlier

          • Naming ions assignment due Tuesday